Question

Possible Duplicate:
increment date by one month

I have the following code to sum dates:

$var1 = date("d/m/Y");
$dia = substr($var1,0,2);
$mes = substr($var1,3,2);
$a_o = substr($var1,6,4);
$date = $a_o."-".$mes."-".$dia;
$new_date = strtotime( "+3 month", strtotime($date));
$new_date = date('d/m/Y', $new_date);
echo $new_date;

That is the normal method I found on php.net but when I tried to change $var1 with another date, for example, '21/07/2020' the result is '31/01/1970', I don’t know what’s wrong. I tried many forms but the result is the same.

How can I fix this? Or what other forms exist to add X months to a date?

Answer 1

Look into the date_add() function that was added for 5.3.0.

DateTime::add — date_add — Adds an amount of days, months, years,
hours, minutes and seconds to a DateTime object

<?php
$date = new DateTime('2000-01-01');
$date->add(new DateInterval('P10D'));
echo $date->format('Y-m-d') . "\n";
?> 

There is also the date_modify() function that was added for 5.2.0.

DateTime::modify — date_modify — Alters the timestamp

<?php
$date = new DateTime('2006-12-12');
$date->modify('+1 day');
echo $date->format('Y-m-d');
?>